Câu 17 :
\(n_{O_2}=a\left(mol\right)\)
\(n_{Fe}=\dfrac{16.8}{56}=0.3\left(mol\right)\)
\(n_{SO_2}=\dfrac{5.6}{22.4}=0.25\left(mol\right)\)
\(Fe\rightarrow Fe^{+3}+3e\)
\(O_2+4e\rightarrow2O^{2-}\)
\(S^{+6}+2e\rightarrow S^{+4}\)
\(\text{Bảo toàn e : }\)
\(4n_{O_2}+2n_{SO_2}=3n_{Fe}\)
\(\Leftrightarrow4a+2\cdot0.25=3\cdot0.3\)
\(\Leftrightarrow x=0.1\)
\(V_{kk}=5V_{O_2}=5\cdot0.1\cdot22.4=11.2\left(l\right)\)
Câu 18 : C
Câu 19 : D
H2S => Xuất hiện kết tủa đen
O2 không hiện tượng
Câu 20:
\(n_{H_2SO_4}=0.1\cdot2=0.2\left(mol\right)\)
\(m_{BaCl_2}=208\cdot15\%=31.2\left(g\right)\)
\(n_{BaCl_2}=\dfrac{31.2}{208}=0.15\left(mol\right)\)
\(BaCl_2+H_2SO_4\rightarrow BaSO_4+2HCl\)
\(0.15............0.15............0.15\)
\(\Rightarrow H_2SO_4\text{dư }\)
\(m_{BaSO_4}=0.15\cdot233=34.95\left(g\right)\)
\(\Rightarrow D\)
